The invention relates to a piston ring, in particular to the compression ring for a piston for internal combustion engines, with the features according to the introductory part of claim 1.
Such a piston ring is known, for example from WO 97/11295 A1, in conjunction with which provision is made for radially extending channels that are distributed over the circumference for reducing the difference pressure acting on the compression ring in the lower flank of the piston ring. Such channels have a height of less than 1 mm, preferably of from 0.35 to 0.55 mm. Nothing is stated in said document as to how said channels, which are relatively deep, are produced.
Furthermore, a piston for internal combustion engines is known from DE 42 05 503 A1, where provision is made for a defined type of profiling extending all around the circumference of a compression ring for the purpose of avoiding damage to the flank of an annular groove.
The drawback with said design is the fact that producing such a phonograph record-like profiling in the flank of the annular groove is difficult and requires much expenditure.
Based on the type of prior art specified above and the problem posed when plating of the flank of a piston ring with a material is to be avoided, in particular of the uppermost compression ring, the problem of the invention is to find a means that leads to a corresponding piston ring in a simple manner and at favorable cost.
Said problem is solved with a piston ring with the features according to the characterizing part of claim 1.
Further advantageous developments of the invention are contained in the dependent claims.